Everyday Science: Iron Quiz

One could safely say that we've built civilization itself on iron -- it's got seemingly infinite uses. From early tools to trains, iron is responsible for thrusting humanity into rapid advancement. But how much do you know about the process of extracting iron from the Earth? Or about the difference between iron and steel? Take our quiz and find out.

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Question 1 of 10

How plentiful is iron in the Earth's crust?

It makes up 0.5 percent of the Earth's crust.

It makes up 5 percent of the Earth's crust.

The Earth's crust is 5 percent iron, and in some areas it concentrates in ores that contain as much as 70 percent iron.

It makes up 25 percent of the Earth's crust.

Question 2 of 10

Which of the following is not true of iron?

It can be magnetized.

It is relatively easy to shape after heating it.

It is naturally resistant to rust.

Although iron can be magnetized and is easy to shape after being heated, it is susceptible to rust. But you can control rust with paint, galvanizing, chrome plating or sacrificial anodes.

Question 3 of 10

Which of the following is a common ore from which we can extract iron?

hematite

Hematite is a common ore that contains about 70 percent iron.

galena

chalcocite

Question 4 of 10

What do you have to eliminate to get iron from iron ore?

hydrogen

nitrogen

oxygen

If you look at the chemical makeup of the various iron ores, they all contain iron combined with oxygen. To make iron from iron ore, you need to eliminate the oxygen.

Question 5 of 10

Which of the following statements about steel and iron is true?

Steel is stronger than iron.

Steel is stronger than iron. Steel is iron that has most of the impurities -- such as silica, phosphorous and sulfur -- removed, making it stronger.

Steel contains more impurities than iron.

Steel is just polished iron.

Question 6 of 10

In a bloomery, iron is heated into a spongy mass known as a bloom. What do you get when you heat and hammer the bloom?

steel

wrought iron

By heating and hammering the bloom, the glassy silicates mix into the iron metal to create wrought iron. Wrought iron is tough and easy to work, making it perfect for creating tools in a blacksmith shop.

pig iron

Question 7 of 10

From pig iron, you can make which of the following?

wrought iron

steel

both of the above

You can make either wrought iron or steel out of pig iron. To create wrought iron, you melt it, mix it with slag and hammer it to eliminate most of the carbon. Steel can be made out of pig iron through the use of an open hearth furnace, a basic oxygen furnace, or using the Bessemer process.

Question 8 of 10

In a blast furnace, what do you call the material that forms when the calcium from limestone combines with silicates?

slag

Slag forms when the calcium in the limestone combines with the silicates. At the bottom of the blast furnace, liquid iron collects along with a layer of slag on top.

coke

rust

Question 9 of 10

What do you add to steel to make stainless-steel?

chromium

Adding 10 percent to 30 percent chromium to steel creates stainless-steel, which is very resistant to rust. The addition of chromium and molybdenum creates chrome-moly steel, which is strong and light.

molybdenum

bleach

Question 10 of 10

When did iron become an important material for human societies?

the 19th century

the Middle Ages

Around 1000 B.C.

Iron became important around 1000 B.C. It was so important that primitive societies are measured by the point at which they learned how to refine iron and enter the Iron Age.